Light-emitting device

ABSTRACT

A light-emitting device or a display device that is less likely to be broken is provided. Provided is a light-emitting device including an element layer and a substrate over the element layer. At least a part of the substrate is bent to the element layer side. The substrate has a light-transmitting property and a refractive index that is higher than that of the air. The element layer includes a light-emitting element that emits light toward the substrate side. Alternatively, provided is a light-emitting device including an element layer and a substrate covering a top surface and at least one side surface of the element layer. The substrate has a light-transmitting property and a refractive index that is higher than that of the air. The element layer includes a light-emitting element that emits light toward the substrate side.

TECHNICAL FIELD

The present invention relates to a light-emitting device, a displaydevice, an electronic device, a lighting device, or a manufacturingmethod thereof. In particular, the present invention relates to alight-emitting device, a display device, an electronic device, or alighting device utilizing electroluminescence (EL) or a manufacturingmethod thereof.

BACKGROUND ART

Recent light-emitting devices and display devices are expected to beapplied to a variety of uses and become diversified.

For example, light-emitting devices and display devices for mobiledevices and the like are required to be thin, lightweight, and lesslikely to be broken. In view of production of high-performance and highvalue-added light-emitting devices and display devices, there are alsodemands for light-emitting devices and display devices capable of touchoperation.

Light-emitting elements utilizing EL (also referred to as EL elements)have features such as ease of thinning and lightening, high-speedresponse to input signal, and driving with a direct-current low voltagesource; therefore, application of the light-emitting elements tolight-emitting devices and display devices has been proposed.

For example, Patent Document 1 discloses a flexible active matrixlight-emitting device in which an organic EL element and a transistorserving as a switching element are provided over a film substrate.

PATENT DOCUMENT

-   [Patent Document 1] Japanese Published Patent Application No.    2003-174153

DISCLOSURE OF INVENTION

An object of one embodiment of the present invention is to provide anovel light-emitting device, display device, electronic device, orlighting device. Another object of one embodiment of the presentinvention is to provide a lightweight light-emitting device, displaydevice, electronic device, or lighting device. Another object of oneembodiment of the present invention is to provide a highly reliablelight-emitting device, display device, electronic device, or lightingdevice. Another object of one embodiment of the present invention is toprovide a light-emitting device, display device, electronic device, orlighting device that is less likely to be broken. Another object of oneembodiment of the present invention is to provide a thin light-emittingdevice, display device, electronic device, or lighting device. Anotherobject of one embodiment of the present invention is to provide alight-emitting device, display device, electronic device, or lightingdevice with high light extraction efficiency. Another object of oneembodiment of the present invention is to provide a light-emittingdevice, display device, electronic device, or lighting device with lowpower consumption.

In one embodiment of the present invention, there is no need to achieveall the above objects.

One embodiment of the present invention is a light-emitting deviceincluding an element layer and a substrate over the element layer. Atleast a part of the substrate is bent to the element layer side. Thesubstrate has a light-transmitting property and a refractive index thatis higher than that of the air. The element layer includes alight-emitting element that emits light toward the substrate side.

In the above structure, it is preferable that at least a part of theelement layer overlap with and be bent in the same direction as aportion of the substrate that is bent to the element layer side.

Another embodiment of the present invention is a light-emitting deviceincluding an element layer and a substrate covering a top surface and atleast one side surface of the element layer. The substrate has alight-transmitting property and a refractive index that is higher thanthat of the air. The element layer includes a light-emitting elementthat emits light toward the substrate side.

Each of the above structures preferably includes a bonding layer betweenthe element layer and the substrate, and the bonding layer preferablyhas a light-transmitting property and a refractive index that is higherthan that of the air. In that case, the bonding layer preferablyincludes a resin and a particle having a refractive index different fromthat of the resin.

In each of the above structures, the element layer preferably includes atouch sensor.

In each of the above structures, the substrate preferably includes anorganic resin. Using an organic resin, not glass, for the substratemakes it possible to provide a light-emitting device that is lightweightand less likely to be broken.

One embodiment of the present invention is a light-emitting device thatincludes an element layer including a first substrate, a first bondinglayer over the first substrate, and a light-emitting element over thefirst bonding layer; a second bonding layer over the element layer; anda second substrate over the second bonding layer. At least part of thesecond substrate is bent to the element layer side. The second bondinglayer and the second substrate each have a light-transmitting propertyand a refractive index higher than that of the air. The light-emittingelement emits light toward the second substrate side.

Another embodiment of the present invention is a light-emitting devicethat includes an element layer including a first substrate, a firstbonding layer over the first substrate, and a light-emitting elementover the first bonding layer; a second substrate covering the topsurface and at least one side surface of the element layer; and a secondbonding layer between the element layer and the second substrate. Thesecond bonding layer and the second substrate each have alight-transmitting property and a refractive index higher than that ofthe air. The light-emitting element emits light toward the secondsubstrate side.

In each of the above structures, the element layer preferably includes alight-receiving element, a light-blocking layer that is closer to thefirst substrate than is the light-receiving element and overlaps withthe light-receiving element, and a sealing layer between thelight-blocking layer and the light-emitting element. The sealing layerpreferably has a refractive index higher than that of the air.

Another embodiment of the present invention is a light-emitting deviceincluding a first substrate, a light-emitting element over the firstsubstrate, a second substrate with a light-transmitting property, alight-blocking layer over the second substrate, a light-receivingelement that is between the second substrate and the light-blockinglayer and overlaps with the light-blocking layer, and a bonding layerformed in a frame shape between the first substrate and the secondsubstrate to surround the light-emitting element and the light-receivingelement. A surface of the first substrate over which the light-emittingelement is formed and a surface of the second substrate over which thelight-receiving element is formed face each other. The light-emittingelement emits light toward the second substrate side.

Another embodiment of the present invention is a light-emitting devicethat includes an element layer including a first substrate, a firstbonding layer over the first substrate, a light-emitting element overthe first bonding layer, a sealing layer over the light-emittingelement, a light-blocking layer over the sealing layer, and alight-receiving element over the light-blocking layer; a secondsubstrate covering the top surface and at least one side surface of theelement layer; and a second bonding layer between the element layer andthe second substrate. The sealing layer, the second bonding layer, andthe second substrate each have a light-transmitting property and arefractive index higher than that of the air. The light-emitting elementemits light toward the second substrate side.

In each of the above structures, a coloring layer overlapping with thelight-emitting element is preferably provided between the sealing layerand the second substrate.

In each of the above structures, the sealing layer preferably includes aresin and a particle having a refractive index different from that ofthe resin.

Embodiments of the present invention also include an electronic deviceincluding the above light-emitting device in a display portion and alighting device including the above light-emitting device in alight-emitting portion.

Note that the light-emitting device in this specification includes, inits category, a display device using a light-emitting element. Further,the category of the light-emitting device in this specification includesa module in which a light-emitting element is provided with a connectorsuch as an anisotropic conductive film or a TCP (tape carrier package);a module having a TCP at the tip of which a printed wiring board isprovided; and a module in which an IC (integrated circuit) is directlymounted on a light-emitting element by a COG (chip on glass) method.Furthermore, the category includes a light-emitting device which is usedin lighting equipment or the like.

In one embodiment of the present invention, a novel light-emittingdevice, display device, electronic device, or lighting device can beprovided. In one embodiment of the present invention, a lightweightlight-emitting device, display device, electronic device, or lightingdevice can be provided. In one embodiment of the present invention, ahighly reliable light-emitting device, display device, electronicdevice, or lighting device can be provided. In one embodiment of thepresent invention, a light-emitting device, display device, electronicdevice, or lighting device that is less likely to be broken can beprovided. In one embodiment of the present invention, a thinlight-emitting device, display device, electronic device, or lightingdevice can be provided. In one embodiment of the present invention, alight-emitting device, display device, electronic device, or lightingdevice with high light extraction efficiency can be provided. In oneembodiment of the present invention, a light-emitting device, displaydevice, electronic device, or lighting device with low power consumptioncan be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1D illustrate examples of a light-emitting device of oneembodiment of the present invention.

FIGS. 2A to 2G illustrate examples of a light-emitting device of oneembodiment of the present invention.

FIGS. 3A and 3B illustrate an example of a light-emitting device of oneembodiment of the present invention.

FIGS. 4A and 4B each illustrate an example of a light-emitting device ofone embodiment of the present invention.

FIGS. 5A and 5B each illustrate an example of a light-emitting device ofone embodiment of the present invention.

FIGS. 6A and 6B each illustrate an example of a light-emitting device ofone embodiment of the present invention.

FIGS. 7A to 7C illustrate an example of a method for manufacturing alight-emitting device of one embodiment of the present invention.

FIGS. 8A to 8C illustrate an example of a method for manufacturing alight-emitting device of one embodiment of the present invention.

FIG. 9 illustrates an example of a light-emitting device of oneembodiment of the present invention.

FIGS. 10A and 10B illustrate an example of a light-emitting device.

FIG. 11 is a photograph of a cross section of a gate pad portion in alight-emitting device in Example.

FIGS. 12A to 12E illustrate steps for manufacturing a light-emittingdevice in Example.

FIGS. 13A to 13F illustrate examples of light-emitting devices.

FIGS. 14A and 14B show photographs of a light-emitting device.

FIGS. 15A to 15D illustrate an example of a light-emitting device of oneembodiment of the present invention.

FIGS. 16A and 16B show photographs of a light-emitting device.

FIGS. 17A and 17B illustrate an example of a light-emitting device ofone embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments will be described in detail with reference to drawings. Notethat the present invention is not limited to the description below, andit is easily understood by those skilled in the art that various changesand modifications can be made without departing from the spirit andscope of the present invention. Therefore, the present invention shouldnot be construed as being limited to the description in the followingembodiments.

Note that in the structures of the invention described below, the sameportions or portions having similar functions are denoted by the samereference numerals in different drawings, and description of suchportions is not repeated. Further, the same hatching pattern is appliedto portions having similar functions, and the portions are notespecially denoted by reference numerals in some cases.

In addition, the position, size, range, or the like of each structureillustrated in drawings and the like is not accurately represented insome cases for easy understanding. Therefore, the disclosed invention isnot necessarily limited to the position, the size, the range, or thelike disclosed in the drawings and the like.

Embodiment 1

In this embodiment, light-emitting devices of embodiments of the presentinvention will be described with reference to FIGS. 1A to 1D and FIGS.2A to 2G.

A light-emitting device of one embodiment of the present inventionincludes an element layer and a substrate over the element layer. Atleast a part of the substrate is bent to the element layer side. Thesubstrate has a light-transmitting property and a refractive index thatis higher than that of the air. The element layer includes alight-emitting element that emits light toward the substrate side.

In one embodiment of the present invention, at least part of thesubstrate on the light extraction side of the light-emitting device isbent to the element layer side; thus, the light-emitting device is lesslikely to be broken. There is no particular limitation on the area orthe position of a region of the substrate that is bent to the elementlayer side, and a bend line may be at the center of the substrate.

<Structural Example 1>

A light-emitting device 100 shown in FIG. 1A includes an element layer101 and a substrate 103 over the element layer 101.

In each of the light-emitting devices described in this embodiment, theelement layer 101 includes a light-emitting element that emits lighttoward the substrate 103 side. In each of the light-emitting devicesdescribed in this embodiment, light emitted from the light-emittingelement included in the element layer 101 is extracted from a lightextraction portion 104 through the substrate 103.

In the light-emitting device 100 in FIG. 1A, at least part of thesubstrate 103 is bent to the element layer 101 side. Specifically, anend portion of the substrate 103 is bent to the element layer 101 side.Here, an “end portion of A” refers to a region including at least a sidesurface of A, and further may include the light extraction portion ofthe light-emitting device. Although end portions including two opposingside surfaces of the substrate 103 are bent to the element layer 101side here, one embodiment of the present invention is not limitedthereto. In addition, although the bend line is parallel to a side ofthe substrate here, one embodiment of the present invention is notlimited thereto. In other words, the bend line may be parallel to anyside of the substrate (either a long side or a short side). Further, thebend line is not necessarily parallel to a side of the substrate.

<Structural Example 2>

A light-emitting device 110 shown in FIG. 1B includes the element layer101, the substrate 103 over the element layer 101, and a bonding layer105 between the element layer 101 and the substrate 103.

At least part of the substrate 103 is bent to the element layer 101side. Further, at least part of the element layer 101 overlaps with andis bent in the same direction as a portion of the substrate 103 that isbent to the element layer 101 side. In other words, and end portion ofthe substrate 103 and an end portion of the element layer 101 are bentto the side opposite to the light extraction side of the light-emittingdevice 110.

<Structural Example 3>

A light-emitting device 120 shown in FIG. 1C is the same as thelight-emitting device 110 in FIG. 1B except for the structure of thelight extraction portion 104. Although only a non-light-emitting portionof the element layer 101 is bent in the light-emitting device 110, alight-emitting portion of the element layer 101 may partly be bent as inthe light-emitting device 120. It can be said that the light extractionportion 104 of the light-emitting device 120 includes a curved surface.

<Structural Example 4>

A light-emitting device 130 shown in FIG. 1D includes the element layer101, the substrate 103 covering the top surface and at least one sidesurface of the element layer 101, and the bonding layer 105 between theelement layer 101 and the substrate 103.

At least part of the substrate 103 is bent to the element layer 101 sideand covers at least part of two side surfaces of the element layer 101.The substrate 103 may cover part of the bottom surface of the elementlayer 101 (the surface opposite to the light-emitting surface of theelement layer).

In each of Structural Examples 1 to 4 of light-emitting devices, atleast part of the substrate 103 on the light extraction side of thelight-emitting device is bent to the element layer 101 side, which makesthe light-emitting device less likely to be broken.

Application Examples 1 to 4 that can be applied to the above structuralexamples of light-emitting devices are described below.

<Application Example 1>

A light-emitting device 140 shown in FIG. 2A is the same as thelight-emitting device 110 in FIG. 1B except that an insulator 107 isprovided. A light-emitting device of one embodiment of the presentinvention includes the insulator 107 on the bottom surface side of theelement layer 101 (the side opposite to the light extraction side of thelight-emitting device). For example, in the case where a conductivelayer is exposed to the air at the bottom surface of the element layer101, the insulator 107 can be provided to electrically insulate thelight-emitting device of one embodiment of the present invention fromanother device. The insulator 107 preferably covers side surfaces of theelement layer 101, the substrate 103, and the bonding layer 105 so thatthese side surfaces are not exposed to the air. Thus, an impurity suchas water can be prevented from entering the light-emitting device.

<Application Example 2>

A light-emitting device 150 shown in FIG. 2B includes one driver circuitportion 106 and one flexible printed circuit (FPC) 108. Although the FPC108 is provided on the substrate 103 side here, the FPC 108 may beprovided on the element layer 101 side. The light-emitting device 150 isthe same as the light-emitting device 110 in FIG. 1B except that thedriver circuit portion 106 and the FPC 108 are provided.

<Application Example 3>

In one embodiment of the present invention, the insulator 107 may coverthe substrate 103 on the light extraction side of the light-emittingdevice (FIG. 2C). This structure reduces damage to the light extractionsurface of the light-emitting device and, further, prevents an elementincluded in the element layer 101 from being broken. Moreover, theinsulator 107 covers side surfaces of the substrate 103 and the elementlayer 101 that are bent to the side opposite to the light extractionside of the light-emitting device. Thus, an impurity such as water canbe prevented from entering the light-emitting device. With such astructure, a highly reliable light-emitting device that is less likelyto be broken can be provided.

<Application Example 4>

In one embodiment of the present invention, a power storage device 111may be placed on the bottom surface side of the element layer 101 (theside opposite to the light extraction side of the light-emitting device)and a protective layer 115 may be provided to cover the power storagedevice 111.

An end portion of the protective layer 115 may overlap with a portion ofthe substrate 103 that is bent to the element layer 101 side (FIG. 2D)or overlap with the element layer 101 without any part of the substrate103 positioned therebetween (FIG. 2E). Further, as shown in FIG. 2F, theinsulator 107 may be provided between the element layer 101 and thepower storage device 111. As shown in FIG. 2G, an end portion of theprotective layer 115 may overlap with the insulator 107 without any partof the substrate 103 positioned therebetween.

In such cases, the FPC on the substrate 103 side or the element layer101 side may be bent to be partly positioned between the element layer101 and the protective layer 115.

In addition, a light-emitting device of one embodiment of the presentinvention may be capable of touch operation. A touch sensor of any ofvarious types such as a resistive type, a capacitive type, an infraredray type, an optical type, an electromagnetic induction type, and asurface acoustic wave type can be used. In one embodiment of the presentinvention, the element layer 101 can be provided with a touch sensorwithout an increase in the number of substrates included in thelight-emitting device. This is preferable because the light-emittingdevice can be thin and lightweight.

Note that it is preferable that the minimum curvature radius in a regionof the substrate 103 that is bent to the element layer 101 side begreater than or equal to 1 mm and less than or equal to 150 mm,preferably greater than or equal to 1 mm and less than or equal to 100mm, further preferably greater than or equal to 1 mm and less than orequal to 50 mm, and particularly preferably greater than or equal to 2mm and less than or equal to 5 mm. Further, it is preferable that theminimum curvature radius in a region of the element layer 101 that isbent in the same direction as the substrate 103 be greater than or equalto 1 mm and less than or equal to 150 mm, preferably greater than orequal to 1 mm and less than or equal to 100 mm, further preferablygreater than or equal to 1 mm and less than or equal to 50 mm, andparticularly preferably greater than or equal to 2 mm and less than orequal to 5 mm. A light-emitting device of one embodiment of the presentinvention is free from breakage of an element even when bent with asmall curvature radius (e.g., greater than or equal to 2 mm and lessthan or equal to 5 mm) and has high reliability. Bending with a smallcurvature radius makes it possible to provide a thin light-emittingdevice. Bending the light extraction portion 104 with a large curvatureradius (e.g., greater than or equal to 5 mm and less than or equal to100 mm) can provide a large display portion (light-emitting portion) ona side surface of a light-emitting device.

<Examples of Materials>

Next, materials and the like that can be used for a light-emittingdevice of one embodiment of the present invention are described.

The element layer 101 includes at least a light-emitting element. As thelight-emitting element, a self-luminous element can be used, and anelement whose luminance is controlled by current or voltage is includedin the category of the light-emitting element. For example, alight-emitting diode (LED), an organic EL element, an inorganic ELelement, or the like can be used.

The element layer 101 may further include a transistor for driving thelight-emitting element, a touch sensor, or the like.

In the element layer 101, the light-emitting element is preferablyprovided between a pair of insulating films with low water permeability.Thus, an impurity such as water can be prevented from entering thelight-emitting element, leading to prevention of a decrease in thereliability of the light-emitting device.

As an insulating film with low water permeability, a film containingnitrogen and silicon (e.g., a silicon nitride film or a silicon nitrideoxide film), a film containing nitrogen and aluminum (e.g., an aluminumnitride film), or the like can be used. Alternatively, a silicon oxidefilm, a silicon oxynitride film, an aluminum oxide film, or the like canbe used.

For example, the water vapor transmittance of the insulating film withlow water permeability is lower than or equal to 1×10⁻⁵ [g/m²·day],preferably lower than or equal to 1×10⁻⁶ [g/m²·day], further preferablylower than or equal to 1×10⁻⁷ [g/m²·day], still further preferably lowerthan or equal to 1×10⁻⁸ [g/m²·day].

The substrate 103 has a light-transmitting property and transmits atleast light emitted from the light-emitting element included in theelement layer 101. The substrate 103 may be a flexible substrate. Therefractive index of the substrate 103 is higher than that of the air.

An organic resin, which has a specific gravity smaller than that ofglass, is preferably used for the substrate 103, in which case thelight-emitting device can be more lightweight as compared with the casewhere glass is used.

Examples of a material having flexibility and a light-transmittingproperty with respect to visible light include glass that is thin enoughto have flexibility, polyester resins such as polyethylene terephthalate(PET) and polyethylene naphthalate (PEN), a polyacrylonitrile resin, apolyimide resin, a polymethyl methacrylate resin, a polycarbonate (PC)resin, a polyethersulfone (PES) resin, a polyamide resin, a cycloolefinresin, a polystyrene resin, a polyamide imide resin, and a polyvinylchloride resin. In particular, a material whose thermal expansioncoefficient is low is preferred, and for example, a polyamide imideresin, a polyimide resin, or PET can be suitably used. A substrate inwhich a glass fiber is impregnated with an organic resin or a substratewhose thermal expansion coefficient is reduced by mixing an organicresin with an inorganic filler can also be used.

The substrate 103 may have a stacked structure of a layer of any of theabove-mentioned materials and a hard coat layer (e.g., a silicon nitridelayer) which protects a surface of the light-emitting device from damageor the like, a layer (e.g., an aramid resin layer) which can dispersepressure, or the like. Furthermore, to suppress a decrease in thelifetime of the light-emitting element due to moisture and the like, theinsulating film with low water permeability may be included in thestacked structure.

The bonding layer 105 has a light-transmitting property and transmits atleast light emitted from the light-emitting element included in theelement layer 101. The refractive index of the bonding layer 105 ishigher than that of the air.

For the bonding layer 105, a resin that is curable at room temperature(e.g., a two-component-mixture-type resin), a light curable resin, athermosetting resin, or the like can be used. Examples of such resinsinclude an epoxy resin, an acrylic resin, a silicone resin, and a phenolresin. In particular, a material with low moisture permeability, such asan epoxy resin, is preferred.

Further, the resin may include a drying agent. For example, a substancethat adsorbs moisture by chemical adsorption, such as oxide of analkaline earth metal (e.g., calcium oxide or barium oxide), can be used.Alternatively, a substance that adsorbs moisture by physical adsorption,such as zeolite or silica gel, may be used. The drying agent ispreferably included because it can prevent an impurity such as moisturefrom entering the light-emitting element, thereby improving thereliability of the light-emitting device.

In addition, it is preferable to mix a filler with a high refractiveindex (e.g., titanium oxide) into the resin, in which case theefficiency of light extraction from the light-emitting element can beimproved.

The bonding layer 105 may also include a scattering member forscattering light. For example, the bonding layer 105 can be a mixture ofthe above resin and particles having a refractive index different fromthat of the resin. The particles function as the scattering member forscattering light.

The difference in refractive index between the resin and the particleswith a refractive index different from that of the resin is preferably0.1 or more, further preferably 0.3 or more. Specifically, an epoxyresin, an acrylic resin, an imide resin, silicone, or the like can beused as the resin, and titanium oxide, barium oxide, zeolite, or thelike can be used as the particles.

Particles of titanium oxide or barium oxide are preferable because theyscatter light excellently. When zeolite is used, it can adsorb watercontained in the resin and the like, thereby improving the reliabilityof the light-emitting element.

To sufficiently function as a scattering member, the particlespreferably have a diameter larger than a visible light wavelength. Evenif the diameter of primary particles is smaller than a visible lightwavelength, secondary particles obtained by aggregation of the primaryparticles can be used as the scattering member. Specifically, thediameter of the particles is preferably greater than or equal to 0.05 μmand less than or equal to 5 μm, further preferably greater than or equalto 0.1 μm and less than or equal to 2 μm. Further, the diameter of theparticles is preferably smaller than half the thickness of the bondinglayer 105.

The bonding layer 105 preferably includes the scattering member so as tohave a haze value of 50% or less, preferably 30% or less, furtherpreferably 10% or less.

The mixture ratio of the particles to the resin can be adjusted asappropriate depending on the refractive index of the resin and thediameter and the refractive index of the particles, and can be higherthan or equal to 1 wt % and lower than or equal to 10 wt %, for example.

In a light-emitting device, a plurality of reflective conductive filmsof light-emitting elements are arranged at regular intervals.Light-emitting devices with improved resolution may have a pixel density(resolution) of 250 ppi or more or, further, 300 ppi or more. When,accordingly, reflective conductive films are arranged at short regularintervals, external light reflected by the conductive films causes astripe pattern on the screen by diffraction grating. There is also aproblem in that the view of the outside is reflected by the conductivefilms to appear on the screen.

When the bonding layer 105 includes a scattering member, even whenexternal light is reflected by an electrode of the light-emittingelement, the reflected light is scattered when it passes through thebonding layer 105. This can make a stripe pattern less likely to becaused on the screen in the light-emitting device of one embodiment ofthe present invention and also reduce reflection of the view of theoutside.

Further, when the bonding layer 105 includes a scattering member, lightcan be scattered at a position closer to a color filter as compared withthe case where a component for scattering light is provided on the outerside of the substrate 103. This makes it possible to prevent uncleardisplay of the light-emitting device due to blur of light extracted fromthe light-emitting element. Specifically, a layer including a scatteringmember is preferably provided in a region within 100 μm, preferably 10μm, further preferably 1 μm from the color filter toward the lightextraction side. This makes it possible to prevent unclear display ofthe light-emitting device due to blur of emitted light.

Such a structure in which the bonding layer 105 includes a scatteringmember is particularly preferable for a high-resolution light-emittingdevice in which adjacent light-emitting elements are close to each otherand reflected light is likely to cause a stripe pattern on the screen,specifically, a light-emitting device with a resolution of 250 ppi ormore, 256 ppi or more, or 300 ppi or more.

The insulator 107 can be formed using any of the organic resins that canbe used for the substrate 103 and the bonding layer 105, or an inorganicinsulating material. The insulator 107 does not necessarily have alight-transmitting property. Note that when the insulator 107 covers thesubstrate 103 on the light extraction side of the light-emitting deviceas in FIG. 2C, an insulating material with a light-transmitting propertyis used for the insulator 107. The substrate 103 and the insulator 107may be attached to each other with an adhesive or the like.

The power storage device 111 includes a storage battery or a capacitorhaving a function of storing electricity. For example, the power storagedevice 111 includes a secondary battery such as a lithium secondarybattery (e.g., a lithium polymer battery using a gel electrolyte), alithium ion battery, a nickel-hydride battery, a nickel-cadmium battery,an organic radical battery, a lead-acid battery, an air secondarybattery, a nickel-zinc battery, or a silver-zinc battery, or a capacitorwith a large capacitance (e.g., a multilayer ceramic capacitor or anelectric double layer capacitor).

The protective layer 115 can be formed using a material similar to thatof the substrate 103, for example. The protective layer 115 does notnecessarily have a light-transmitting property. It is also possible touse a thin metal material or a thin alloy material for the protectivelayer 115.

As described above, in the light-emitting device of one embodiment ofthe present invention, at least part of the substrate is bent to theelement layer side; thus, the light-emitting device is less likely to bebroken. Further, since an organic resin or the like is used for thesubstrate, the light-emitting device can be lightweight. Thus, with oneembodiment of the present invention, a light-emitting device with highportability can be provided.

Moreover, in the light-emitting device of one embodiment of the presentinvention, the bonding layer 105 includes a scattering member; thus,reflected light can be prevented from causing a stripe pattern on thescreen. Although it is also possible to provide a circularly polarizingplate or the like to prevent a stripe pattern from being caused,providing a circularly polarizing plate greatly reduces the amount oflight extracted from the light-emitting element. In that case, theluminance of the light-emitting element must be increased so thatrequired luminance of the light-emitting device is obtained, whichresults in increased power consumption of the light-emitting device. Inone embodiment of the present invention, a stripe pattern can beprevented from being caused, without a decrease in the amount of lightextracted from the light-emitting element. Thus, with one embodiment ofthe present invention, a light-emitting device with high lightextraction efficiency and low power consumption can be provided.

This embodiment can be combined with any other embodiment asappropriate.

Embodiment 2

In this embodiment, a light-emitting device of one embodiment of thepresent invention is described with reference to FIGS. 3A and 3B, FIGS.4A and 4B, FIGS. 5A and 5B, FIGS. 6A and 6B, FIGS. 7A to 7C, and FIGS.8A to 8C.

<Specific Example 1>

FIG. 3A is a plan view of the light-emitting device 150 (FIG. 2B)described as an example in Embodiment 1, and FIG. 3B is an example of across-sectional view taken along dashed-dotted line A1-A2 in FIG. 3A.

The light-emitting device shown in FIG. 3B includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes a substrate 201, a bonding layer 203, an insulating layer 205,a plurality of transistors, a conductive layer 157, an insulating layer207, an insulating layer 209, a plurality of light-emitting elements, aninsulating layer 211, a sealing layer 213, an insulating layer 261, acoloring layer 259, a light-blocking layer 257, and an insulating layer255.

The conductive layer 157 is electrically connected to the FPC 108 via aconnector 215.

A light-emitting element 230 includes a lower electrode 231, an EL layer233, and an upper electrode 235. The lower electrode 231 is electricallyconnected to a source electrode or a drain electrode of a transistor240. An end portion of the lower electrode 231 is covered with theinsulating layer 211. The light-emitting element 230 has a top emissionstructure. The upper electrode 235 has a light-transmitting property andtransmits light emitted from the EL layer 233.

The coloring layer 259 is provided to overlap with the light-emittingelement 230, and the light-blocking layer 257 is provided to overlapwith the insulating layer 211. The coloring layer 259 and thelight-blocking layer 257 are covered with the insulating layer 261. Thespace between the light-emitting element 230 and the insulating layer261 is filled with the sealing layer 213.

The light-emitting device includes a plurality of transistors includingthe transistor 240 in the light extraction portion 104 and the drivercircuit portion 106. The transistor 240 is provided over the insulatinglayer 205. The insulating layer 205 and the substrate 201 are attachedto each other with the bonding layer 203. The insulating layer 255 andthe substrate 103 are attached to each other with the bonding layer 105.It is preferable to use films with low water permeability for theinsulating layer 205 and the insulating layer 255, in which case animpurity such as water can be prevented from entering the light-emittingelement 230 or the transistor 240, leading to improved reliability ofthe light-emitting device. The bonding layer 203 can be formed using amaterial similar to that of the bonding layer 105.

The light-emitting device in Specific Example 1 can be manufactured inthe following manner: the insulating layer 205, the transistor 240, andthe light-emitting element 230 are formed over a formation substratewith high heat resistance; the formation substrate is separated; and theinsulating layer 205, the transistor 240, and the light-emitting element230 are transferred to the substrate 201 and attached thereto with thebonding layer 203. The light-emitting device in Specific Example 1 canbe manufactured in the following manner: the insulating layer 255, thecoloring layer 259, and the light-blocking layer 257 are formed over aformation substrate with high heat resistance; the formation substrateis separated; and the insulating layer 255, the coloring layer 259, andthe light-blocking layer 257 are transferred to the substrate 103 andattached thereto with the bonding layer 105.

In the case where a material with low heat resistance (e.g., resin) isused for a substrate, it is difficult to expose the substrate to hightemperature in the manufacturing process. Thus, there is a limitation onconditions for forming a transistor and an insulating film over thesubstrate. Further, in the case where a material with high waterpermeability (e.g., resin) is used for a substrate of a light-emittingdevice, it is preferable to expose the substrate to high temperature andform a film with low water permeability between the substrate and alight-emitting element. In the manufacturing method of this embodiment,a transistor and the like can be formed over a formation substratehaving high heat resistance; thus, the substrate can be exposed to hightemperature and a highly reliable transistor and an insulating film withsufficiently low water permeability can be formed. Then, the transistorand the insulating film are transferred to a substrate with low heatresistance, whereby a highly reliable light-emitting device can bemanufactured. Thus, with one embodiment of the present invention, a thinor/and lightweight light-emitting device with high reliability can beprovided. Details of the manufacturing method will be described later.

The substrate 103 and the substrate 201 are each preferably formed usinga material with high toughness. Thus, a light-emitting device with highimpact resistance that is less likely to be broken can be provided. Forexample, when the substrate 103 is an organic resin substrate and thesubstrate 201 is a substrate formed using a thin metal material or athin alloy material, the light-emitting device can be more lightweightand less likely to be broken as compared with the case where a glasssubstrate is used.

A metal material and an alloy material, which have high thermalconductivity, are preferred because they can easily conduct heat to thewhole substrate and accordingly can prevent a local temperature rise inthe light-emitting device. The thickness of a substrate using a metalmaterial or an alloy material is preferably greater than or equal to 10μm and less than or equal to 200 μm, further preferably greater than orequal to 20 μm and less than or equal to 50 μm.

Further, when a material with high thermal emissivity is used for thesubstrate 201, the surface temperature of the light-emitting device canbe prevented from rising, leading to prevention of breakage or adecrease in reliability of the light-emitting device. For example, thesubstrate 201 may have a stacked structure of a metal substrate and alayer with high thermal emissivity (the layer can be formed using ametal oxide or a ceramic material, for example).

<Specific Example 2>

FIG. 4A shows another example of the light extraction portion 104 in thelight-emitting device of one embodiment of the present invention. Thelight-emitting device shown in FIG. 4A is capable of touch operation. Inthe following specific examples, description of components similar tothose in Specific Example 1 is omitted.

The light-emitting device shown in FIG. 4A includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, the insulating layer 207, theinsulating layer 209, a plurality of light-emitting elements, theinsulating layer 211, an insulating layer 217, the sealing layer 213,the insulating layer 261, the coloring layer 259, the light-blockinglayer 257, a plurality of light-receiving elements, a conductive layer281, a conductive layer 283, an insulating layer 291, an insulatinglayer 293, an insulating layer 295, and the insulating layer 255.

Specific Example 2 includes the insulating layer 217 over the insulatinglayer 211. The space between the substrate 103 and the substrate 201 canbe adjusted with the insulating layer 217.

FIG. 4A shows an example in which a light-receiving element is providedbetween the insulating layer 255 and the sealing layer 213. Since thelight-receiving element can be placed to overlap with anon-light-emitting region (e.g., a region where the light-emittingelement is not provided, such as a region where a transistor or a wiringis provided) of the light-emitting device, the light-emitting device canbe provided with a touch sensor without a decrease in the aperture ratioof a pixel (light-emitting element).

As the light-receiving element included in the light-emitting device ofone embodiment of the present invention, for example, a pn photodiode ora pin photodiode can be used. In this embodiment, a pin photodiodeincluding a p-type semiconductor layer 271, an i-type semiconductorlayer 273, and an n-type semiconductor layer 275 is used as thelight-receiving element.

Note that the i-type semiconductor layer 273 is a semiconductor in whichthe concentration of each of an impurity imparting p-type conductivityand an impurity imparting n-type conductivity is 1×10²⁰ cm⁻³ or less andwhich has photoconductivity 100 times or more as high as darkconductivity. The i-type semiconductor layer 273 also includes, in itscategory, a semiconductor that contains an impurity element belonging toGroup 13 or Group 15 of the periodic table. In other words, since ani-type semiconductor has weak n-type electric conductivity when animpurity element for controlling valence electrons is not addedintentionally, the i-type semiconductor layer 273 includes, in itscategory, a semiconductor to which an impurity element imparting p-typeconductivity is added intentionally or unintentionally at the time ofdeposition or after the deposition.

The light-blocking layer 257 is closer to the substrate 201 than is thelight-receiving element and overlaps with the light-receiving element.The light-blocking layer 257 between the light-receiving element and thesealing layer 213 can prevent the light-receiving element from beingirradiated with light emitted from the light-emitting element 230.

The conductive layer 281 and the conductive layer 283 are electricallyconnected to the light-receiving element. The conductive layer 281preferably transmits light incident on the light-receiving element. Theconductive layer 283 preferably blocks light incident on thelight-receiving element.

It is preferable to provide an optical touch sensor between thesubstrate 103 and the sealing layer 213 because the optical touch sensoris less likely to be affected by light emitted from the light-emittingelement 230 and can have improved S/N ratio.

<Specific Example 3>

FIG. 4B shows another example of the light extraction portion 104 in thelight-emitting device of one embodiment of the present invention. Thelight-emitting device shown in FIG. 4B is capable of touch operation.

The light-emitting device shown in FIG. 4B includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, the insulating layer 207, an insulatinglayer 209 a, an insulating layer 209 b, a plurality of light-emittingelements, the insulating layer 211, the insulating layer 217, thesealing layer 213, the coloring layer 259, the light-blocking layer 257,a plurality of light-receiving elements, a conductive layer 280, theconductive layer 281, and the insulating layer 255.

FIG. 4B shows an example in which a light-receiving element is providedbetween the insulating layer 205 and the sealing layer 213. Since thelight-receiving element is provided between the insulating layer 205 andthe sealing layer 213, a conductive layer to which the light-receivingelement is electrically connected and a photoelectric conversion layerincluded in the light-receiving element can be formed using the samematerials and the same steps as a conductive layer and a semiconductorlayer included in the transistor 240. Thus, the light-emitting devicecapable of touch operation can be manufactured without a significantincrease in the number of manufacturing steps.

<Specific Example 4>

FIG. 5A shows another example of a light-emitting device of oneembodiment of the present invention. The light-emitting device shown inFIG. 5A is capable of touch operation.

The light-emitting device shown in FIG. 5A includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, a conductive layer 156, the conductivelayer 157, the insulating layer 207, the insulating layer 209, aplurality of light-emitting elements, the insulating layer 211, theinsulating layer 217, the sealing layer 213, the coloring layer 259, thelight-blocking layer 257, the insulating layer 255, a conductive layer272, a conductive layer 274, an insulating layer 276, an insulatinglayer 278, a conductive layer 294, and a conductive layer 296.

FIG. 5A shows an example in which a capacitive touch sensor is providedbetween the insulating layer 255 and the sealing layer 213. Thecapacitive touch sensor includes the conductive layer 272 and theconductive layer 274.

The conductive layer 156 and the conductive layer 157 are electricallyconnected to the FPC 108 via the connector 215. The conductive layer 294and the conductive layer 296 are electrically connected to theconductive layer 274 via conductive particles 292. Thus, the capacitivetouch sensor can be driven via the FPC 108.

<Specific Example 5>

FIG. 5B shows another example of a light-emitting device of oneembodiment of the present invention. The light-emitting device shown inFIG. 5B is capable of touch operation.

The light-emitting device shown in FIG. 5B includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 201, the bonding layer 203, the insulating layer205, a plurality of transistors, the conductive layer 156, theconductive layer 157, the insulating layer 207, the insulating layer209, a plurality of light-emitting elements, the insulating layer 211,the insulating layer 217, the sealing layer 213, the coloring layer 259,the light-blocking layer 257, the insulating layer 255, a conductivelayer 270, the conductive layer 272, the conductive layer 274, theinsulating layer 276, and the insulating layer 278.

FIG. 5B shows an example in which a capacitive touch sensor is providedbetween the insulating layer 255 and the sealing layer 213. Thecapacitive touch sensor includes the conductive layer 272 and theconductive layer 274.

The conductive layer 156 and the conductive layer 157 are electricallyconnected to an FPC 108 a via a connector 215 a. The conductive layer270 is electrically connected to an FPC 108 b via a connector 215 b.Thus, the light-emitting element 230 and the transistor 240 can bedriven via the FPC 108 a, and the capacitive touch sensor can be drivenvia the FPC 108 b.

<Specific Example 6>

FIG. 6A shows another example of the light extraction portion 104 in thelight-emitting device of one embodiment of the present invention.

The light-emitting device shown in FIG. 6A includes the element layer101, the substrate 103, and the bonding layer 105. The element layer 101includes a substrate 202, the insulating layer 205, a plurality oftransistors, the insulating layer 207, a conductive layer 208, theinsulating layer 209 a, the insulating layer 209 b, a plurality oflight-emitting elements, the insulating layer 211, the sealing layer213, and the coloring layer 259.

The light-emitting element 230 includes the lower electrode 231, the ELlayer 233, and the upper electrode 235. The lower electrode 231 iselectrically connected to the source electrode or the drain electrode ofthe transistor 240 via the conductive layer 208. An end portion of thelower electrode 231 is covered with the insulating layer 211. Thelight-emitting element 230 has a bottom emission structure. The lowerelectrode 231 has a light-transmitting property and transmits lightemitted from the EL layer 233.

The coloring layer 259 is provided to overlap with the light-emittingelement 230, and light emitted from the light-emitting element 230 isextracted from the substrate 103 side through the coloring layer 259.The space between the light-emitting element 230 and the substrate 202is filled with the sealing layer 213. The substrate 202 can be formedusing a material similar to that of the substrate 201.

<Specific Example 7>

FIG. 6B shows another example of a light-emitting device of oneembodiment of the present invention.

The light-emitting device shown in FIG. 6B includes the element layer101, the bonding layer 105, and the substrate 103. The element layer 101includes the substrate 202, the insulating layer 205, a conductive layer310 a, a conductive layer 310 b, a plurality of light-emitting elements,the insulating layer 211, a conductive layer 212, and the sealing layer213.

The conductive layer 310 a and the conductive layer 310 b, which areexternal connection electrodes of the light-emitting device, can each beelectrically connected to an FPC or the like.

The light-emitting element 230 includes the lower electrode 231, the ELlayer 233, and the upper electrode 235. An end portion of the lowerelectrode 231 is covered with the insulating layer 211. Thelight-emitting element 230 has a bottom emission structure. The lowerelectrode 231 has a light-transmitting property and transmits lightemitted from the EL layer 233. The conductive layer 212 is electricallyconnected to the lower electrode 231.

The substrate 103 may have, as a light extraction structure, ahemispherical lens, a micro lens array, a film provided with an unevensurface structure, a light diffusing film, or the like. For example, thesubstrate 103 with a light extraction structure can be formed byattaching the above lens or film to a resin substrate with an adhesiveor the like having substantially the same refractive index as thesubstrate or the lens or film.

The conductive layer 212 is preferably, though not necessarily, providedbecause voltage drop due to the resistance of the lower electrode 231can be prevented. In addition, for a similar purpose, a conductive layerelectrically connected to the upper electrode 235 may be provided overthe insulating layer 211, the EL layer 233, the upper electrode 235, orthe like.

The conductive layer 212 can be a single layer or a stacked layer formedusing a material selected from copper, titanium, tantalum, tungsten,molybdenum, chromium, neodymium, scandium, nickel, or aluminum, an alloymaterial containing any of these materials as its main component, or thelike. The thickness of the conductive layer 212 can be, for example,greater than or equal to 0.1 um and less than or equal to 3 um,preferably greater than or equal to 0.1 um and less than or equal to 0.5um.

When a paste (e.g., silver paste) is used as a material for theconductive layer electrically connected to the upper electrode 235,metal particles forming the conductive layer aggregate; therefore, thesurface of the conductive layer is rough and has many gaps. Thus, evenwhen the conductive layer is formed over the insulating layer 211, forexample, it is difficult for the EL layer 233 to completely cover theconductive layer; accordingly, the upper electrode and the conductivelayer are electrically connected to each other easily, which ispreferable.

<Examples of Materials>

Next, materials and the like that can be used for a light-emittingdevice of one embodiment of the present invention are described.Description on the substrate 103 and the bonding layer 105 is omittedbecause the description in Embodiment 1 can be referred to. Further,description on the components already described in this embodiment isalso omitted.

The structure of the transistors in the light-emitting device is notparticularly limited. For example, a forward staggered transistor or aninverted staggered transistor may be used. A top-gate transistor or abottom-gate transistor may be used. A semiconductor material used forthe transistors is not particularly limited, and for example, silicon orgermanium can be used. Alternatively, an oxide semiconductor containingat least one of indium, gallium, and zinc, such as an In—Ga—Zn-basedmetal oxide, may be used.

There is no particular limitation on the crystallinity of asemiconductor material used for the transistors, and an amorphoussemiconductor or a semiconductor having crystallinity (amicrocrystalline semiconductor, a polycrystalline semiconductor, asingle-crystal semiconductor, or a semiconductor partly includingcrystal regions) may be used. It is preferable that a semiconductorhaving crystallinity be used, in which case deterioration of thetransistor characteristics can be suppressed.

The light-emitting element included in the light-emitting deviceincludes a pair of electrodes (the lower electrode 231 and the upperelectrode 235); and the EL layer 233 between the pair of electrodes. Oneof the pair of electrodes functions as an anode and the other functionsas a cathode.

The light-emitting element may have any of a top emission structure, abottom emission structure, and a dual emission structure. A conductivefilm that transmits visible light is used as the electrode through whichlight is extracted. A conductive film that reflects visible light ispreferably used as the electrode through which light is not extracted.

The conductive film that transmits visible light can be formed using,for example, indium oxide, indium tin oxide (ITO), indium zinc oxide,zinc oxide, or zinc oxide to which gallium is added. Alternatively, afilm of a metal material such as gold, silver, platinum, magnesium,nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium,or titanium; an alloy containing any of these metal materials; or anitride of any of these metal materials (e.g., titanium nitride) can beformed thin so as to have a light-transmitting property. Alternatively,a stack of any of the above materials can be used as the conductivefilm. For example, a stacked film of ITO and an alloy of silver andmagnesium is preferably used, in which case conductivity can beincreased. Further alternatively, graphene or the like may be used.

For the conductive film that reflects visible light, for example, ametal material such as aluminum, gold, platinum, silver, nickel,tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium or analloy containing any of these metal materials can be used. Further,lanthanum, neodymium, germanium, or the like may be added to the metalmaterial or the alloy. Furthermore, an alloy containing aluminum (analuminum alloy) such as an alloy of aluminum and titanium, an alloy ofaluminum and nickel, or an alloy of aluminum and neodymium; or an alloycontaining silver such as an alloy of silver and copper, an alloy ofsilver, copper, and palladium, or an alloy of silver and magnesium canbe used for the conductive film. An alloy of silver and copper ispreferable because of its high heat resistance. Further, when a metalfilm or a metal oxide film is stacked on and in contact with an aluminumalloy film, oxidation of the aluminum alloy film can be prevented.Examples of a material for the metal film or the metal oxide film aretitanium and titanium oxide. Alternatively, the above conductive filmthat transmits visible light and a film containing a metal material maybe stacked. For example, a stacked film of silver and ITO or a stackedfilm of an alloy of silver and magnesium and ITO can be used.

Each of the electrodes can be formed by an evaporation method or asputtering method. Alternatively, a discharging method such as an inkjetmethod, a printing method such as a screen printing method, or a platingmethod may be used.

When a voltage higher than the threshold voltage of the light-emittingelement is applied between the lower electrode 231 and the upperelectrode 235, holes are injected to the EL layer 233 from the anodeside and electrons are injected to the EL layer 233 from the cathodeside. The injected electrons and holes are recombined in the EL layer233 and a light-emitting substance contained in the EL layer 233 emitslight.

The EL layer 233 includes at least a light-emitting layer. In additionto the light-emitting layer, the EL layer 233 may further include one ormore layers containing any of a substance with a high hole-injectionproperty, a substance with a high hole-transport property, ahole-blocking material, a substance with a high electron-transportproperty, a substance with a high electron-injection property, asubstance with a bipolar property (a substance with a high electron- andhole-transport property), and the like.

For the EL layer 233, either a low molecular compound or a highmolecular compound can be used, and an inorganic compound may also beused. Each of the layers included in the EL layer 233 can be formed byany of the following methods: an evaporation method (including a vacuumevaporation method), a transfer method, a printing method, an inkjetmethod, a coating method, and the like.

The insulating layer 205 and the insulating layer 255 can each be formedusing an inorganic insulating material. It is particularly preferable touse the insulating film with low water permeability, in which case ahighly reliable light-emitting device can be provided.

The insulating layer 207 has an effect of preventing diffusion ofimpurities into a semiconductor included in the transistor. As theinsulating layer 207, an inorganic insulating film such as a siliconoxide film, a silicon oxynitride film, a silicon nitride film, a siliconnitride oxide film, or an aluminum oxide film can be used.

As each of the insulating layers 209, 209 a, and 209 b, an insulatingfilm with a planarization function is preferably selected in order toreduce surface unevenness due to the transistor or the like. Forexample, an organic material such as a polyimide resin, an acrylicresin, or a benzocyclobutene-based resin can be used. Other than suchorganic materials, it is also possible to use a low-dielectric constantmaterial (a low-k material) or the like. Note that the planarizationinsulating film may have a stacked structure of any of insulating filmsformed of these materials and inorganic insulating films.

The insulating layer 211 is provided to cover an end portion of thelower electrode 231. In order that the insulating layer 211 be favorablycovered with the EL layer 233 and the upper electrode 235 formedthereover, a side wall of the insulating layer 211 preferably has atilted surface with continuous curvature.

As a material for the insulating layer 211, a resin or an inorganicinsulating material can be used. As the resin, for example, a polyimideresin, a polyamide resin, an acrylic resin, a siloxane resin, an epoxyresin, or a phenol resin can be used. In particular, either a negativephotosensitive resin or a positive photosensitive resin is preferablyused for easy formation of the insulating layer 211.

There is no particular limitation to the method for forming theinsulating layer 211; a photolithography method, a sputtering method, anevaporation method, a droplet discharging method (e.g., an inkjetmethod), a printing method (e.g., a screen printing method or an off-setprinting method), or the like may be used.

The insulating layer 217 can be formed using an inorganic insulatingmaterial, an organic insulating material, or the like. As the organicinsulating material, for example, a negative or positive photosensitiveresin, a non-photosensitive resin, or the like can be used. Instead ofthe insulating layer 217, a conductive layer may be formed. For example,the conductive layer can be formed using a metal material such astitanium or aluminum. When a conductive layer is used instead of theinsulating layer 217 and the conductive layer is electrically connectedto the upper electrode 235, voltage drop due to the resistance of theupper electrode 235 can be prevented. The insulating layer 217 may haveeither a tapered shape or an inverse tapered shape.

Each of the insulating layers 276, 278, 291, 293, and 295 can be formedusing an inorganic insulating material or an organic insulatingmaterial. It is particularly preferable to use an insulating film with aplanarization function for each of the insulating layers 278 and 295 inorder to reduce surface unevenness due to a sensor element.

For the sealing layer 213, a resin that is curable at room temperature(e.g., a two-component-mixture-type resin), a light curable resin, athermosetting resin, or the like can be used. For example, a polyvinylchloride (PVC) resin, an acrylic resin, a polyimide resin, an epoxyresin, a silicone resin, a polyvinyl butyral (PVB) resin, an ethylenevinyl acetate (EVA) resin, or the like can be used. A drying agent maybe contained in the sealing layer 213. In the case where light emittedfrom the light-emitting element 230 is extracted outside through thesealing layer 213, the sealing layer 213 preferably includes a fillerwith a high refractive index or a scattering member. Materials for thedrying agent, the filler with a high refractive index, and thescattering member are similar to those that can be used for the bondinglayer 105.

Each of the conductive layers 156, 157, 294, and 296 can be formed usingthe same material and the same step as a conductive layer included inthe transistor or the light-emitting element. The conductive layer 280can be formed using the same material and the same step as a conductivelayer included in the transistor.

For example, each of the conductive layers can be formed to have asingle-layer structure or a stacked-layer structure using any of metalmaterials such as molybdenum, titanium, chromium, tantalum, tungsten,aluminum, copper, neodymium, and scandium, and an alloy materialcontaining any of these elements. Each of the conductive layers may beformed using a conductive metal oxide. As the conductive metal oxide,indium oxide (e.g., In₂O₃), tin oxide (e.g., SnO₂), zinc oxide (ZnO),ITO, indium zinc oxide (e.g., In₂O₃—ZnO), or any of these metal oxidematerials in which silicon oxide is contained can be used.

Each of the conductive layers 208, 212, 310 a, and 310 b can also beformed using any of the above metal materials, alloy materials, andconductive metal oxides.

Each of the conductive layers 272, 274, 281, and 283 is a conductivelayer with a light-transmitting property. The conductive layer can beformed using, for example, indium oxide, ITO, indium zinc oxide, zincoxide, zinc oxide to which gallium is added, or the like. The conductivelayer 270 can be formed using the same material and the same step as theconductive layer 272.

As the conductive particles 292, particles of an organic resin, silica,or the like coated with a metal material are used. It is preferable touse nickel or gold as the metal material because contact resistance canbe reduced. It is also preferable to use particles each coated withlayers of two or more kinds of metal materials, such as particles coatedwith nickel and further with gold.

For the connector 215, it is possible to use a paste-like or sheet-likematerial which is obtained by mixture of metal particles and athermosetting resin and for which anisotropic electric conductivity isprovided by thermocompression bonding. As the metal particles, particlesin which two or more kinds of metals are layered, for example, nickelparticles coated with gold are preferably used.

The coloring layer 259 is a colored layer that transmits light in aspecific wavelength range. For example, a red (R) color filter fortransmitting light in a red wavelength range, a green (G) color filterfor transmitting light in a green wavelength range, a blue (B) colorfilter for transmitting light in a blue wavelength range, or the likecan be used. Each coloring layer is formed in a desired position withany of various materials by a printing method, an inkjet method, anetching method using a photolithography method, or the like.

The light-blocking layer 257 is provided between the adjacent coloringlayers 259. The light-blocking layer 257 blocks light emitted from theadjacent light-emitting element, thereby preventing color mixturebetween adjacent pixels. Here, the coloring layer 259 is provided suchthat its end portion overlaps with the light-blocking layer 257, wherebylight leakage can be reduced. The light-blocking layer 257 can be formedusing a material that blocks light emitted from the light-emittingelement, for example, a metal material, a resin material including apigment or a dye, or the like. Note that the light-blocking layer 257 ispreferably provided in a region other than the light extraction portion104, such as the driver circuit portion 106, as illustrated in FIG. 3B,in which case undesired leakage of guided light or the like can beprevented.

The insulating layer 261 covering the coloring layer 259 and thelight-blocking layer 257 is preferably provided because it can preventan impurity such as a pigment included in the coloring layer 259 or thelight-blocking layer 257 from diffusing into the light-emitting elementor the like. For the insulating layer 261, a light-transmitting materialis used, and an inorganic insulating material or an organic insulatingmaterial can be used. The insulating film with low water permeabilitymay be used for the insulating layer 261. Note that the insulating layer261 is not necessarily provided.

<Example of Manufacturing Method>

Next, an example of a method for manufacturing a light-emitting deviceof one embodiment of the present invention will be described withreference to FIGS. 7A to 7C and FIGS. 8A to 8C. Here, the manufacturingmethod is described using the light-emitting device of Specific Example1 (FIG. 3B) as an example.

First, a separation layer 303 is formed over a formation substrate 301,and the insulating layer 205 is formed over the separation layer 303.Next, the plurality of transistors, the conductive layer 157, theinsulating layer 207, the insulating layer 209, the plurality oflight-emitting elements 230, and the insulating layer 211 are formedover the insulating layer 205. An opening is formed in the insulatinglayers 211, 209, and 207 to expose the conductive layer 157 (FIG. 7A).

In addition, a separation layer 307 is formed over a formation substrate305, and the insulating layer 255 is formed over the separation layer307. Next, the light-blocking layer 257, the coloring layer 259, and theinsulating layer 261 are formed over the insulating layer 255 (FIG. 7B).

The formation substrate 301 and the formation substrate 305 can each bea glass substrate, a quartz substrate, a sapphire substrate, a ceramicsubstrate, a metal substrate, or the like.

For the glass substrate, for example, a glass material such asaluminosilicate glass, aluminoborosilicate glass, or barium borosilicateglass can be used. When the temperature of heat treatment performedlater is high, a substrate having a strain point of 730° C. or higher ispreferably used. Note that when containing a large amount of bariumoxide (BaO), the glass substrate can be heat-resistant and morepractical. Alternatively, crystallized glass or the like may be used.

In the case where a glass substrate is used as the formation substrate,an insulating film such as a silicon oxide film, a silicon oxynitridefilm, a silicon nitride film, or a silicon nitride oxide film ispreferably formed between the formation substrate and the separationlayer, in which case contamination from the glass substrate can beprevented.

The separation layer 303 and the separation layer 307 each have asingle-layer structure or a stacked-layer structure containing anelement selected from tungsten, molybdenum, titanium, tantalum, niobium,nickel, cobalt, zirconium, zinc, ruthenium, rhodium, palladium, osmium,iridium, and silicon; an alloy material containing any of the elements;or a compound material containing any of the elements. A crystalstructure of a layer containing silicon may be amorphous, microcrystal,or polycrystal.

The separation layer can be formed by a sputtering method, a plasma CVDmethod, a coating method, a printing method, or the like. Note that acoating method includes a spin coating method, a droplet dischargemethod, and a dispensing method.

In the case where the separation layer has a single-layer structure, atungsten layer, a molybdenum layer, or a layer containing a mixture oftungsten and molybdenum is preferably formed. Alternatively, a layercontaining an oxide or an oxynitride of tungsten, a layer containing anoxide or an oxynitride of molybdenum, or a layer containing an oxide oran oxynitride of a mixture of tungsten and molybdenum may be formed.Note that the mixture of tungsten and molybdenum corresponds to an alloyof tungsten and molybdenum, for example.

In the case where the separation layer is formed to have a stacked-layerstructure including a layer containing tungsten and a layer containingan oxide of tungsten, the layer containing an oxide of tungsten may beformed as follows: the layer containing tungsten is formed first and aninsulating film formed of an oxide is formed thereover, so that thelayer containing an oxide of tungsten is formed at the interface betweenthe tungsten layer and the insulating film. Alternatively, the layercontaining an oxide of tungsten may be formed by performing thermaloxidation treatment, oxygen plasma treatment, nitrous oxide (N₂O) plasmatreatment, treatment with a highly oxidizing solution such as ozonewater, or the like on the surface of the layer containing tungsten.Plasma treatment or heat treatment may be performed in an atmosphere ofoxygen, nitrogen, or nitrous oxide alone, or a mixed gas of any of thesegasses and another gas. Surface condition of the separation layer ischanged by the plasma treatment or heat treatment, whereby adhesionbetween the separation layer and the insulating layer formed later canbe controlled.

Each of the insulating layers can be formed by a sputtering method, aplasma CVD method, a coating method, a printing method, or the like. Forexample, the insulating layer is formed at a temperature of higher thanor equal to 250° C. and lower than or equal to 400° C. by a plasma CVDmethod, whereby the insulating layer can be a dense film with very lowwater permeability.

Then, a material for the sealing layer 213 is applied to a surface ofthe formation substrate 305 over which with the coloring layer 259 andthe like are formed or a surface of the formation substrate 301 overwhich the light-emitting element 230 and the like are formed, and theformation substrate 301 and the formation substrate 305 are attached sothat these two surfaces face each other with the sealing layer 213positioned therebetween (FIG. 7C).

Next, the formation substrate 301 is separated, and the exposedinsulating layer 205 and the substrate 201 are attached to each otherwith the bonding layer 203. Further, the formation substrate 305 isseparated, and the exposed insulating layer 255 and the substrate 103are attached to each other with the bonding layer 105. Although thesubstrate 103 does not overlap with the conductive layer 157 in FIG. 8A,the substrate 103 may overlap with the conductive layer 157.

Any of a variety of methods can be used as appropriate for theseparation process. For example, when a layer including a metal oxidefilm is formed as the separation layer on the side in contact with thelayer to be separated, the metal oxide film is embrittled bycrystallization, whereby the layer to be separated can be separated fromthe formation substrate. Alternatively, when an amorphous silicon filmcontaining hydrogen is formed as the separation layer between theformation substrate having high heat resistance and the layer to beseparated, the amorphous silicon film is removed by laser lightirradiation or etching, whereby the layer to be separated can beseparated from the formation substrate. Alternatively, after a layerincluding a metal oxide film is formed as the separation layer on theside in contact with the layer to be separated, the metal oxide film isembrittled by crystallization, and part of the separation layer isremoved by etching using a solution or a fluoride gas such as NF₃, BrF₃,or ClF₃, whereby the separation can be performed at the embrittled metaloxide film. Furthermore, a method may be used in which a film containingnitrogen, oxygen, hydrogen, or the like (for example, an amorphoussilicon film containing hydrogen, an alloy film containing hydrogen, analloy film containing oxygen, or the like) is used as the separationlayer, and the separation layer is irradiated with laser light torelease the nitrogen, oxygen, or hydrogen contained in the separationlayer as a gas, thereby promoting separation between the layer to beseparated and the formation substrate. Alternatively, it is possible touse a method in which the formation substrate provided with the layer tobe separated is removed mechanically or by etching using a solution or afluoride gas such as NF₃, BrF₃, or ClF₃, or the like. In this case, theseparation layer is not necessarily provided.

Further, the separation process can be conducted easily by combinationof the above-described separation methods. In other words, separationcan be performed with physical force (by a machine or the like) afterperforming laser light irradiation, etching on the separation layer witha gas, a solution, or the like, or mechanical removal with a sharpknife, scalpel or the like so that the separation layer and the layer tobe separated can be easily separated from each other.

Separation of the layer to be separated from the formation substrate maybe carried out by filling the interface between the separation layer andthe layer to be separated with a liquid. Further, the separation may beconducted while pouring a liquid such as water.

As another separation method, in the case where the separation layer isformed using tungsten, it is preferable that the separation be performedwhile etching the separation layer using a mixed solution of ammoniumwater and a hydrogen peroxide solution.

Note that the separation layer is not necessary in the case whereseparation at the interface between the formation substrate and thelayer to be separated is possible. For example, glass is used as theformation substrate, an organic resin such as polyimide, polyester,polyolefin, polyamide, polycarbonate, or acrylic is formed in contactwith the glass, and an insulating film, a transistor, and the like areformed over the organic resin. In this case, heating the organic resinenables the separation at the interface between the formation substrateand the organic resin. Alternatively, separation at the interfacebetween a metal layer and the organic resin may be performed in thefollowing manner: the metal layer is provided between the formationsubstrate and the organic resin and current is made to flow in the metallayer so that the metal layer is heated.

Lastly, an opening is formed in the insulating layer 255 and the sealinglayer 213 to expose the conductive layer 157 (FIG. 8B). FIG. 13A is aplan view at this stage. In the case where the substrate 103 overlapswith the conductive layer 157, the opening is formed also in thesubstrate 103 and the bonding layer 105 so that the conductive layer 157is exposed (FIG. 8C). The method for forming the opening is notparticularly limited and may be, for example, a laser ablation method,an etching method, an ion beam sputtering method, or the like. Asanother method, a cut may be made in a film over the conductive layer157 with a sharp knife or the like and part of the film may be separatedby physical force.

In the above-described manner, the light-emitting device of oneembodiment of the present invention can be manufactured.

As described above, a light-emitting device of one embodiment of thepresent invention includes two substrates; one is the substrate 103 andthe other is the substrate 201 or the substrate 202. The light-emittingdevice can be formed with two substrates even when including a touchsensor. Owing to the use of the minimum number of substrates,improvement in light extraction efficiency and improvement in clarity ofdisplay can be easily achieved.

This embodiment can be combined with any other embodiment asappropriate.

Embodiment 3

In this embodiment, a light-emitting device of one embodiment of thepresent invention will be described with reference to FIG. 9.

The light-emitting device shown in FIG. 9 includes a substrate 401, thetransistor 240, the light-emitting element 230, the insulating layer207, the insulating layer 209, the insulating layer 211, the insulatinglayer 217, a space 405, the insulating layer 261, the light-blockinglayer 257, the coloring layer 259, a light-receiving element (includingthe p-type semiconductor layer 271, the i-type semiconductor layer 273,and the n-type semiconductor layer 275), the conductive layer 281, theconductive layer 283, the insulating layer 291, the insulating layer293, the insulating layer 295, and a substrate 403.

The light-emitting device includes a bonding layer (not shown) formed ina frame shape between the substrate 401 and the substrate 403 tosurround the light-emitting element 230 and the light-receiving element.The light-emitting element 230 is sealed by the bonding layer, thesubstrate 401, and the substrate 403.

In the light-emitting device of this embodiment, the substrate 403 has alight-transmitting property. Light emitted from the light-emittingelement 230 is extracted to the air through the coloring layer 259, thesubstrate 403, and the like.

The light-emitting device of this embodiment is capable of touchoperation. Specifically, proximity or contact of an object on a surfaceof the substrate 403 can be sensed with the light-receiving element.

An optical touch sensor is highly durable and preferable because itssensing accuracy is not affected by damage to a surface that is touchedby an object. An optical touch sensor is also advantageous in that it iscapable of noncontact sensing, it does not degrade the clarity of imageswhen used in a display device, and it is applicable to large-sizedlight-emitting devices and display devices.

It is preferable to provide an optical touch sensor between thesubstrate 403 and the space 405 because the optical touch sensor is lesslikely to be affected by light emitted from the light-emitting element230 and can have improved S/N ratio.

The light-blocking layer 257 is closer to the substrate 401 than is thelight-receiving element and overlaps with the light-receiving element.The light-blocking layer 257 can prevent the light-receiving elementfrom being irradiated with light emitted from the light-emitting element230.

There is no particular limitation on materials used for the substrates401 and 403. The substrate through which light emitted from thelight-emitting element is extracted is formed using a material thattransmits the light. For example, a material such as glass, quartz,ceramics, sapphire, or an organic resin can be used. Since the substratethrough which light is not extracted does not need a light-transmittingproperty, a metal substrate or the like using a metal material or analloy material can be used as well as the above-mentioned substrates.Further, any of the materials for the substrates given in the aboveembodiments can also be used for the substrates 401 and 403.

A method for sealing the light-emitting device is not limited, andeither solid sealing or hollow sealing can be employed. For example, asa sealing material, a glass material such as a glass frit, or a resinmaterial such as a resin that is curable at room temperature (e.g., atwo-component-mixture-type resin), a light curable resin, or athermosetting resin can be used. The space 405 may be filled with aninert gas such as nitrogen or argon, or with a resin or the like similarto that used for the sealing layer 213. Further, the resin may includethe drying agent, the filler with a high refractive index, or thescattering member.

This embodiment can be combined with any other embodiment asappropriate.

EXAMPLE

In this example, a light-emitting device of one embodiment of thepresent invention is described.

In this example, first, the element layer 101, the bonding layer 105,and the substrate 103 were stacked. The thickness of this stackedstructure was 140 μm. Then, an end portion of the substrate 103 and anend portion of the element layer 101 were bent to the side opposite tothe light extraction side of the light-emitting device. After that, theinsulator 107 was provided. The insulator 107 covers side surfaces ofthe element layer 101, the substrate 103, and the bonding layer 105 toprevent entry of an impurity such as moisture to the element layer 101.Further, the insulator 107 increases the strength of a connectionportion 119 between the element layer 101 and the FPC 108, therebyimproving the reliability of the light-emitting device.

FIG. 10A is a plan view of the light-emitting device fabricated in thisexample. FIG. 10B is a cross-sectional view taken along dashed-dottedlines A3-A4 and A5-A6 in FIG. 10A.

Note that description on components of the light-emitting device in thisexample that are similar to those of Specific Example 2 (FIG. 4A)described in Embodiment 2 is omitted in some cases.

The light-emitting device in this example includes, as shown in FIG.10A, the light extraction portion 104, a connection portion 112, a gateline driver circuit 113, a gate pad portion 114, a source pad portion116, the connection portion 119, an IC 118 for a source line drivercircuit, and the FPC 108.

Description on the structure of the light extraction portion 104 in FIG.10B is omitted because the structure is similar to that in FIG. 4A.

In the connection portion 112 in FIG. 10B, a conductive layer 234 andthe upper electrode 235 are stacked and electrically connected to eachother. The conductive layer 234 is formed using the same material andthe same step as the lower electrode 231 of the light-emitting element230. The upper electrode 235 is connected to the conductive layer 234 inan opening in the insulating layer 211.

In the gate pad portion 114 in FIG. 10B, a gate line 241 that is formedusing the same material and the same step as a gate electrode of thetransistor 240, a conductive layer 244 that is formed using the samematerial and the same step as a source electrode and a drain electrodeof the transistor 240, and a conductive layer 232 that is formed usingthe same material and the same step as the lower electrode 231 of thelight-emitting element 230 are stacked and electrically connected toeach other. The conductive layer 244 is connected to the gate line 241in an opening in a gate insulating film 242. The conductive layer 232 isconnected to the conductive layer 244 in an opening in the insulatinglayers 207 and 209.

The gate pad portion 114 at the end of a gate line and the source padportion 116 at the end of a source line can be used for inspection ofthe transistor or failure analysis of the light-emitting device. Forexample, it is possible to check whether signals are properly input tothe gate line from the gate line driver circuit 113 by using the gatepad portion 114.

The upper electrode 235 of the light-emitting element 230 is providedover the conductive layer 232 with the insulating layers 211 and 217positioned therebetween. Here, when the insulating layers 211 and 217are thin, the conductive layer 232 and the upper electrode 235 might beshort-circuited. Therefore, the insulating layers that electricallyinsulate the conductive layer 232 and the upper electrode 235 arepreferably thick enough.

FIG. 11 shows a cross section of the gate pad portion 114 that isobserved by scanning transmission electron microscopy (STEM).

As indicated by the region surrounded by a dotted line, the conductivelayer 232 and the upper electrode 235 are electrically insulated by thestacked structure of the insulating layers 211 and 217. Thus, a shortcircuit between the conductive layer 232 and the upper electrode 235 isprevented and line defects in the light-emitting device can be reduced.Note that the insulating layers 211 and 217 are formed using the samematerial; therefore, the boundary between the insulating layers is notclear in FIG. 11. The insulating layers 211 and 217 may be formed usingdifferent materials.

As shown in FIG. 12A, end portions of the light-emitting device (seeFIGS. 10A and 10B) were bent to the element layer 101 side. As indicatedby the dashed-dotted line in FIG. 13B, the bend lines are parallel tosides of the substrate. Here, end portions of the substrate 103, thebonding layer 105, and the element layer 101 were bent to the elementlayer 101 side. The curvature radius of a side surface of thelight-emitting device was 4 mm. As shown in FIG. 13B, part of thelight-emitting portion (light extraction portion 104) was bent to makethe light-emitting device emit light from a side surface as well as thetop surface.

As shown in FIG. 13C, the width of a region of the element layer 101that does not overlap with the substrate 103 may be smaller than that ofthe substrate 103 and end portions of the element layer 101 may be bentonly in regions that overlap with the substrate 103. It is also possibleto employ a structure in which the width of the whole element layer 101is smaller than that of the substrate 103 and the element layer 101 isnot bent.

FIG. 13D is a plan view of the rear side of the light-emitting device inFIG. 12A (i.e., the light extraction side).

Then, the light-emitting device bent into the shape shown in FIG. 12Awas put in a mold 299 shown in FIG. 12B and fixed. The mold is notnecessarily composed of one member, and may be composed of a pluralityof members as shown in FIG. 12C, for example.

A resin was poured into the mold 299 with the light-emitting device keptin the mold 299 (FIG. 12D) and the resin was cured, whereby theinsulator 107 was formed. In this example, an epoxy resin, whichtransmits visible light, was used as the resin.

The insulator 107 may be formed only on the bottom surface side of theelement layer 101 (the side opposite to the light extraction side of thelight-emitting device) as shown in FIG. 2A, or may also cover the lightextraction surface of the light-emitting device as shown in FIG. 2C. Forexample, on the light extraction side of the light-emitting device, itis preferable that the insulator 107 not be formed in a regionoverlapping with the light extraction portion 104 in order to prevent adecrease in the light extraction efficiency of the light-emittingdevice.

For example, the insulator 107 can be prevented from being formed in theregion overlapping with the light extraction portion 104 on the lightextraction side of the light-emitting device in the following manner:the insulator 107 is formed with a separate film for protecting thesurface provided on the substrate 103, and then the separate film ispeeled off.

In addition, it is preferable to form the insulator 107 in a regionoverlapping with the connection portion 119 to increase the strength ofa crimp portion of the FPC 108, which is on the light extraction side ofthe light-emitting device. Note that the strength of the crimp portioncan be increased with a resin other than the insulator 107, a tape, orthe like.

In the above manner, the light-emitting device of one embodiment of thepresent invention in which at least part of the substrate on the lightextraction side of the light-emitting device is bent to the elementlayer side was fabricated (FIG. 12E).

FIG. 13E is a plan view of the light extraction side of thelight-emitting device in FIG. 12E. FIG. 13F is a plan view of the lightextraction side of the light-emitting device showing the case where theinsulator 107 covers the light extraction surface of the light-emittingdevice.

FIGS. 14A and 14B show a light-emitting device of one embodiment of thepresent invention that was fabricated. The thickness of thelight-emitting device was 8000 μm.

It is also possible to make the light-emitting device of one embodimentof the present invention be able to be switched between display using aside surface and display not using a side surface (using only the frontsurface). The side surface and the front surface may display independentimages or display one image; further, switching between these two modesis possible.

FIGS. 15A to 15D illustrate an example in which an end portion includingone side surface of the substrate 103 is bent to the element layer 101side. FIG. 15A illustrates perspective views of a light-emitting device160 of one embodiment of the present invention viewed from threedirections.

FIGS. 15B to 15D illustrate a portable information terminal 300 usingsuch a light-emitting device. FIG. 15B is a perspective viewillustrating an external shape of the portable information terminal 300.FIG. 15C is a top view of the portable information terminal 300. FIG.15D illustrates a use state of the portable information terminal 300.

The portable information terminal 300 serves as one or more of atelephone set, an electronic notebook, an information browsing system,and the like, for example. Specifically, the portable informationterminal 300 can be used as a smartphone.

The portable information terminal 300 can display characters and imageinformation on its plurality of surfaces. For example, three operationbuttons 109 can be displayed on one surface (FIG. 15B). Further,information 117 indicated by dashed rectangles can be displayed onanother surface (FIG. 15C). Examples of the information 117 includecontents of notification from a social networking service (SNS), displayindicating reception of an e-mail or an incoming call, the title of ane-mail or the like, the sender of an e-mail or the like, the date, thetime, remaining battery, and the reception strength of an antenna.Alternatively, the operation button 109, an icon, or the like may bedisplayed in place of the information 117. Although FIGS. 15B and 15Cshow the example in which the information 117 is displayed at the top,one embodiment of the present invention is not limited thereto. Forexample, as shown in FIGS. 17A and 17B, the information may be displayedon the side.

Since the portable information terminal 300 can perform display on aside surface as shown in FIG. 15C, a user can see the display with theportable information terminal 300 put in a breast pocket of his/herclothes, for example (FIG. 15D).

Specifically, a caller's phone number, name, or the like of an incomingcall is displayed in a position that can be observed from above theportable information terminal 300. Thus, the user can see the displaywithout taking out the portable information terminal 300 from thepocket. Accordingly, the user can receive an incoming call when it is anurgent call or reject an incoming call when it is an unnecessary call.

Note that the portable information terminal 300 can be provided with avibration sensor or the like and a memory device with a program forshifting a mode into an incoming call rejection mode in accordance withvibration sensed by the vibration sensor or the like. Thus, the user canshift the mode into the incoming call rejection mode by tapping theportable information terminal 300 over his/her clothes so as to applyvibration.

FIGS. 16A and 16B show a light-emitting device of one embodiment of thepresent invention that was fabricated. Note that the structures of theelement layer 101, the bonding layer 105, and the substrate 103 aresimilar to those in FIGS. 10A and 10B.

EXPLANATION OF REFERENCE

100: light-emitting device, 101: element layer, 103: substrate, 104:light extraction portion, 105: bonding layer, 106: driver circuitportion, 107: insulator, 108: FPC, 108 a: FPC, 108 b: FPC, 109:operation button, 110: light-emitting device, 111: power storage device,112: connection portion, 113: gate line driver circuit, 114: gate padportion, 115: protective layer, 116: source pad portion, 117:information, 118: IC, 119: connection portion, 120: light-emittingdevice, 130: light-emitting device, 140: light-emitting device, 150:light-emitting device, 156: conductive layer, 157: conductive layer,160:

light-emitting device, 201: substrate, 202: substrate, 203: bondinglayer, 205: insulating layer, 207: insulating layer, 208: conductivelayer, 209: insulating layer, 209 a: insulating layer, 209 b: insulatinglayer, 211: insulating layer, 212: conductive layer, 213: sealing layer,215: connector, 215 a: connector, 215 b: connector, 217: insulatinglayer, 230: light-emitting element, 231: lower electrode, 232:conductive layer, 233: EL layer, 234: conductive layer, 235: upperelectrode, 240: transistor, 241: gate line, 242: gate insulating film,244: conductive layer, 255: insulating layer, 257: light-blocking layer,259: coloring layer, 261: insulating layer, 270: conductive layer, 271:p-type semiconductor layer, 272: conductive layer, 273: i-typesemiconductor layer, 274: conductive layer, 275: n-type semiconductorlayer, 276: insulating layer, 278: insulating layer, 280: conductivelayer, 281: conductive layer, 283: conductive layer, 291: insulatinglayer, 292: conductive particle, 293: insulating layer, 294: conductivelayer, 295: insulating layer, 296: conductive layer, 301: formationsubstrate, 303: separation layer, 305: formation substrate, 307:separation layer, 310 a: conductive layer, 310 b: conductive layer, 401:substrate, 403: substrate, 405: space.

This application is based on Japanese Patent Application serial no.2013-084528 filed with Japan Patent Office on Apr. 15, 2013 and JapanesePatent Application serial no. 2013-218603 filed with Japan Patent Officeon Oct. 21, 2013, the entire contents of which are hereby incorporatedby reference.

What is claimed is:
 1. A manufacturing method of a light-emittingdevice, comprising steps of: forming a transistor over a firstsubstrate; forming a light-emitting element over the transistor; forminga first conductive layer over the light-emitting element; forming aninsulating layer over the first conductive layer; forming a secondconductive layer over the insulating layer; and forming a secondsubstrate over the second conductive layer, wherein a third conductivelayer is formed using a same material and through a same process as thesecond conductive layer, wherein the third conductive layer iselectrically connected to a flexible printed circuit, wherein the thirdconductive layer serves as an external connection electrode, wherein thetransistor and the light-emitting element are in a pixel region, whereinthe first conductive layer and the second conductive layer overlap witheach other in the pixel region with the insulating layer therebetween,wherein the third conductive layer is outside the pixel region, whereinthe second substrate comprises a flat region and a first region which isbent to the first substrate side, wherein the pixel region and the firstregion overlap with each other, wherein the third conductive layer andthe flat region overlap with each other, and wherein the light-emittingdevice is configured to sense proximity or contact of an object on a topsurface of the second substrate using the first conductive layer and thesecond conductive layer.
 2. The manufacturing method according to claim1, further comprising a step of forming a resin layer between thelight-emitting element and the first conductive layer, wherein the resinlayer serves as sealing the light-emitting element.
 3. The manufacturingmethod according to claim 1, wherein the light-emitting device isconfigured to drive the first conductive layer and the second conductivelayer through the flexible printed circuit.
 4. The manufacturing methodaccording to claim 1, wherein the second substrate comprises a secondregion which is bent to the first substrate side, wherein the flatregion is between the first region and the second region, and whereinthe pixel region and the second region overlap with each other.
 5. Themanufacturing method according to claim 1, wherein a refractive index ofthe second substrate is higher than that of a refractive index of theair.
 6. The manufacturing method according to claim 1, wherein thetransistor comprises an oxide semiconductor layer comprising indium,gallium, and zinc.
 7. A light-emitting device comprising: a transistorover a first substrate; a light-emitting element over the transistor; afirst conductive layer over the light-emitting element; an insulatinglayer over the first conductive layer; a second conductive layer overthe insulating layer; and a second substrate over the second conductivelayer, wherein a third conductive layer is formed using a same materialas the second conductive layer, wherein the third conductive layer iselectrically connected to a flexible printed circuit, wherein the thirdconductive layer serves as an external connection electrode, wherein thetransistor and the light-emitting element are in a pixel region, whereinthe first conductive layer and the second conductive layer overlap witheach other in the pixel region with the insulating layer therebetween,wherein the third conductive layer is outside the pixel region, whereinthe second substrate comprises a flat region and a first region which isbent to the first substrate side, wherein the pixel region and the firstregion overlap with each other, wherein the third conductive layer andthe flat region overlap with each other, and wherein the light-emittingdevice is configured to sense proximity or contact of an object on a topsurface of the second substrate using the first conductive layer and thesecond conductive layer.
 8. The light-emitting device according to claim7, further comprising a step of forming a resin layer between thelight-emitting element and the first conductive layer, wherein the resinlayer serves as sealing the light-emitting element.
 9. Thelight-emitting device according to claim 7, wherein the light-emittingdevice is configured to drive the first conductive layer and the secondconductive layer through the flexible printed circuit.
 10. Thelight-emitting device according to claim 7, wherein the second substratecomprises a second region which is bent to the first substrate side,wherein the flat region is between the first region and the secondregion, and wherein the pixel region and the second region overlap witheach other.
 11. The light-emitting device according to claim 7, whereina refractive index of the second substrate is higher than that of arefractive index of the air.
 12. The light-emitting device according toclaim 7, wherein the transistor comprises an oxide semiconductor layercomprising indium, gallium, and zinc.